QuestionÌý What is the prevalence of heart failure with preserved ejection fraction (HFpEF) in severe isolated secondary tricuspid regurgitation (TR), and how do noninvasive measures perform in its detection?

FindingsÌý In this cross-sectional study of 54 patients with isolated severe TR referred for invasive hemodynamic exercise testing, HFpEF was diagnosed in 74% but had been recognized in only 35% prior to invasive evaluation. Guideline-defined echocardiographic criteria for diastolic dysfunction missed 60% of HFpEF cases.

MeaningÌý HFpEF should be suspected in patients with apparently isolated secondary TR, and a low threshold to refer for invasive testing should be considered as these patients may benefit from effective therapies for HFpEF beyond TR-specific interventions.

ImportanceÌý Secondary tricuspid regurgitation (STR) is observed in multiple cardiac and pulmonary diseases. Heart failure with preserved ejection fraction (HFpEF) is a common cause of STR that may be overlooked, along with precapillary etiologies of pulmonary hypertension (PH).

ObjectivesÌý To investigate the prevalence of HFpEF and precapillary PH in patients with severe STR of undefined etiology (isolated STR) referred for exercise right heart catheterization (RHC), and to evaluate the performance of noninvasive measures to identify HFpEF.

Design, Setting, and ParticipantsÌý This retrospective cross-sectional study included consecutive adults with severe STR in the absence of EF less than 50%, hemodynamically significant left-sided valve disease, congenital heart disease, infiltrative or hypertrophic cardiomyopathy, pericardial disease, or prior cardiac procedures who underwent rest-and-exercise RHC between February 2006 and June 2023 at Mayo Clinic and transthoracic echocardiography less than 90 days prior. Diastolic dysfunction (DD) was defined by at least 3 of 4 or 2 of 3 abnormal diastolic parameters (medial e’, medial E/e’, tricuspid regurgitation [TR] velocity, left atrial volume index). HFpEF was diagnosed when pulmonary arterial wedge pressure was at least 15 mm Hg at rest, at least 19 mm Hg with feet up, or at least 25 mm Hg during exercise. Data analysis was performed from November 2023 to March 2024.

Main Outcomes and MeasuresÌý The prevalence of HFpEF and precapillary PH in severe isolated STR was determined, and performance of noninvasive measures to identify HFpEF was evaluated.

ResultsÌý Overall, 54 patients with severe isolated STR (mean [SD] age, 70.8 [12.5] years; 34 [63%] female) were identified. The primary indication for RHC was evaluation of TR prior to potential intervention in 36 patients (67%), evaluation of PH in 13 (24%), and confirmation of HFpEF in 5 (9%). HFpEF was identified in 40 patients (74%) but was recognized prior to RHC in only 19 patients (35%). Of the 14 remaining patients without HFpEF, precapillary PH was diagnosed in 10 (71%). Guideline-defined DD was absent in 24 patients (60%) who were subsequently diagnosed with HFpEF. Left atrial emptying fraction (area under the receiver operating characteristic curve [AUC] = 0.90; 95% CI, 0.82-0.98) and strain (AUC = 0.91; 95% CI, 0.83-0.99) had robust discrimination for HFpEF.

Conclusions and RelevanceÌý The findings suggest that HFpEF is underdiagnosed and should be rigorously evaluated for in patients with severe isolated STR, along with precapillary PH, as both have distinct requirements for management. Resting DD based on current guidelines is insufficiently sensitive in these patients, indicating a pressing need for other noninvasive diagnostic tools, such as left atrial function assessment.